"Everything changes and nothing stands still."
- You could not step twice into the same river.
As quoted in Plato, Cratylus, 402a:
"Soc. Heracleitus is supposed to say that all things are in motion and nothing at rest; he compares them to the stream of a river, and says that you cannot go into the same water twice.”
From Heraclitus, Plato, and many other ancient writers Blake got his fundamental principle of opposites.
Matter is composed of dualities
"Joy and woe are woven fine,A clothing for the soul divine;
Under every grief and pine
Runs a joy with silken twine …"
Ability (to something) - inability
Abnormal - normal
Absence of sympathy - sympathy
Absolute - relative (especially pertinent to Blake)
Abstract - specific (especially pertinent to Blake)
2. enslav'd the vulgar by attempting to realize or abstract the
The Marriage of Heaven and Hell, 11; E38
3. With cold floods of abstraction, and with forests of solitude,
VISIONS of the Daughters of Albion, 5.19; E49
4. The Human Abstract.
Songs of Experience, Title; E27)
Acceptable - unacceptable
Active - passive
All - nothing
Altruism - egoism
Always - never
An observer - an observed
Analysis - synthesis
Some of Blake's Uses:
Songs of Innocence and Experience
Eden and Beulah
Marriage of Heaven and Hell
The point is that in 'this world' we are dualistic.
In Eternity we are whole.